The present invention relates to a process for the refining of sulfidic concentrates which contain arsenic, antimony and/or bismuth, wherein a suspension of sulfidic concentrates and oxygen, and possibly oxygen-enriched air, is introduced into the upper part of the reaction zone, in the lower part of which the direction of the gases is deflected sidewards in order to cause the molten and solid particles traveling along with them to impinge against the surface of the melt below the reaction zone.
A process is known from U.S. Pat. No. 1 762 867 for the treatment of complex ores which contain metal sulfide, wherein the ore is heated for a selective evaporation of the metal sulfides, a reducing atmosphere being maintained within the raw material and directly above it, and an oxidizing atmosphere further above. When necessary, sulfur can be added to the raw material. The smelting of the raw material and its oxidation to the desired metal concentration must, however, be carried out in a separate stage.
FI-Pat. No. 56 196 discloses a process for bringing the impurities, such as arsenic, antimony and bismuth, present in sulfidic complex and mixed ores and concentrates into an easily removable form, wherein the minerals of the raw material are broken up and rearranged at temperatures below 900.degree. C. and at a high partial pressure of elemental sulfur, i.e. 0.2-1 atm, in such a way that new, easily volatilizing independent sulfide compounds are formed, which can be in part volatilized in the same stage.
This prior known process has a disadvantage in that by means of it the impurities of the raw material are only brought to an easily removable form, whereas the actual smelting must be carried out in a separate stage.
The object of the present invention is to eliminate this disadvantage and to provide a process for the removal of arsenic, antimony and bismuth from sulfidic concentrates and for the smelting of the matte in one single stage, for example in the reaction shaft of a flash smelting furnace.